Valves and valve systems are used to control pressure within containers and flow into and out of containers. For example, angle valves and check valves can be used in combination to control flow of fluid into and/or out of tanks. In this regard, check valves are used in addition to angle valves for a number of reasons. For example, check valves are sometimes used to prevent back flow of fluid. Check valves are also sometimes used to minimize the wear on the angle valve that might result from the high pressure within the tank. In yet another form, check valves might be used to minimize the contact between the fluid and the angle valve to lessen the wear on the angle valve that might occur from corrosive or other fluids maintained in the tank.
Such valves and valve systems can be utilized in a number of applications. For example, these valve systems are often used in rail cars for transporting fluids, including liquids and/or gas. Generally, rail cars include at least one location on the car where inlet and outlet valves may be located, along with other related devices, such as pressure control valves, gauges and other structures. However, generally these valves, including pressure relief valves, are often located on an exterior of the rail car. By having the valves located on the exterior of the rail car, the valves are more prone to being damaged and/or accidentally removed if contacted by other machinery or if the rail car were to overturn.
Valves, including overpressure valves, are also used on other containers such as ISO and tote tanks. In general, an ISO tank is a pressure vessel mounted in a frame that complies with the standards of the International Standards Organization (ISO). ISO and tote tanks are commonly used for transporting chemicals, especially internationally. In some instances, these types of tanks are approximately one quarter the size of rail cars. Additionally, the tanks are built with frames or other structural support surrounding the tank to protect the tank and allow it to sit squarely on the ground or on top of other tanks. These types of tanks can be transported in a number of ways, including, but not limited to, rail, truck and sea.
ISO and tote tanks generally include similar valves and valve systems to those described with respect to rail cars. For example, ISO and tote tanks may include overpressure valves and/or rupture discs for preventing the tanks from rupturing during an overpressure situation. Just as described with respect to rail cars, ISO and tote tanks are also susceptible to tipping over and/or having the valves damaged or broken off by other machinery.
However, conventional angle valve and check valve combinations are often designed and installed such that they are an interconnected unit. In this regard, it can become dangerous if the angle valve is sheared off or damaged while in operation because the connection of the check valve might also be damaged. Further, angle valves typically extend a significant distance from the tank, thereby increasing the chance that the valve is damaged or sheared off. Additionally, once installed, angle valves and check valves can be problematic to replace or maintain. For example, oftentimes, the entire angle valve and check valve combination must be removed to replace parts on either of the angle valve or check valve. Such a removal process is time consuming and costly.